Glossary
Decentralization
The property of a system whose operation, ownership, and decision-making are distributed across many independent participants instead of one operator.
Decentralization is what lets a blockchain resist censorship and single points of failure: with thousands of nodes validating the same rules, no single party can rewrite history, freeze funds, or take the network offline without coordinating a majority.
In practice it is a spectrum measured across several axes — node count and geography, mining/staking concentration, client diversity, governance, and hosting providers — and most chains are more decentralized in some dimensions than others.